Rescue tools known as "jaws of life" devices are specialized tools used by various rescue personnel such as police, firemen, paramedics generally for the purpose of extricating accident victims from vehicles whose exits have been rendered inoperable. These tools require spreading and closing forces for opening or ripping apart inoperable doors or for cutting through relatively thick metal layers. Pushing and pulling forces of 7,000 to 15,000 pounds at the tips are considered to be normal for the proper operation of such tools. In the past, in order to achieve such high forces, the tools have been almost exclusively hydraulic and powered by gasoline engines, for example as described in U.S. Pat. No. 4,842,249.
With self contained hydraulic and gasoline units the tools were sufficiently portable for use under adverse conditions commonly encountered with the rescue of accident victims. Nevertheless, many "portable" units weigh in excess of 200 pounds and require at least two persons for operation.
Some tools, such as described in U.S. Pat. No. 4,896,862 are designed as separate jaw elements for use with various available powered inputs such as a pneumatic or hydraulic pumps or electric motors which drive threaded actuating elements. Though described as being powered with an electric motor, most devices are powered by gasoline or other fuel operated devices which provide the requisite driving power in a portable fashion. Electric power sources are not readily available in most emergency situations and portable batteries have not been considered capable of providing the requisite torque for effective operation of such devices.
As a result of the widespread use of hydraulic systems with fuel operated powering, as a general proposition, many of the existing tools also require constant costly maintenance of various components in order to maintain effectiveness.
Major drawbacks for most hydraulic system tools include their inability to generate full tip spreading force upon initial spreading application, the position at which such forces are needed most. Gasoline powered hydraulic devices are also very noisy and because of fuel containment exigencies, require special transport compartments. Other severe drawbacks include their detrimental susceptibility to environmental conditions including explosive atmospheres and inclement weather. A gasoline powered unit is dangerous to operate under many accident conditions wherein the speed required in the rescue is that of saving a victim from imminent harm in spreading flames.